London milliner Vivian Tremont and her American cousin and partner, Scarlett Parker, tip their caps to their beloved shop on Portobello Road in Notting Hill and set off for Paris, where Viv can't wait to teach a hat-making class. But she has another reason to travel to the City of Light: to find the man she impulsively eloped with years ago and have their marriage annulled.

William Graham is not only handsome and charming, but he also has a glamorous job as an insurance investigator who works with priceless pieces of art, most recently a small Renoir that has been discovered in a junk shop. But when both Will and the masterpiece suddenly disappear, it's up to the ladies from London to follow the trail of clues. They'll need to hold on to their chapeaux, however, because someone is a master in the art of deception...